5.
Mapping Factory

An important decision in the object-relational mapping process is how and where
to store the data necessary to map your persistent classes to the database
schema.

Section 1, “
Metadata Factory
” introduced OpenJPA's
MetaDataFactory interface. OpenJPA uses this same interface to
abstract the storage and retrieval of mapping information. OpenJPA includes the
built-in mapping factories below, and you can create your own factory if you
have custom needs. You control which mapping factory OpenJPA uses with the
openjpa.jdbc.MappingFactory configuration property.

The bundled mapping factories are:

-: Leaving the openjpa.jdbc.MappingFactory
property unset allows your metadata factory to take over mappings as
well. If you are using the default jpa metadata factory,
OpenJPA will read mapping information from your annotations and
orm.xml when you leave the mapping factory unspecified.